Gritzner Christian, Dürfeld Kai, Kasper Jan, Fasoulas Stefanos
Institute for Aerospace Engineering, Technische Universität Dresden, 01062, Dresden, Germany.
Naturwissenschaften. 2006 Aug;93(8):361-73. doi: 10.1007/s00114-006-0115-0.
The impact of extraterrestrial matter onto Earth is a continuous process. On average, some 50,000 tons of dust are delivered to our planet every year. While objects smaller than about 30 m mainly disintegrate in the Earth's atmosphere, larger ones can penetrate through it and cause damage on the ground. When an object of hundreds of meters in diameter impacts an ocean, a tsunami is created that can devastate coastal cities. Further, if a km-sized object hit the Earth it would cause a global catastrophe due to the transport of enormous amounts of dust and vapour into the atmosphere resulting in a change in the Earth's climate. This article gives an overview of the near-Earth asteroid and comet (near-Earth object-NEO) impact hazard and the NEO search programmes which are gathering important data on these objects. It also points out options for impact hazard mitigation by using deflection systems. It further discusses the critical constraints for NEO deflection strategies and systems as well as mitigation and evacuation costs and benefits. Recommendations are given for future activities to solve the NEO impact hazard problem.
地外物质对地球的撞击是一个持续的过程。平均而言，每年约有5万吨尘埃落到我们的星球上。小于约30米的物体主要在地球大气层中解体，而较大的物体则可以穿透大气层并在地面造成破坏。当一个直径数百米的物体撞击海洋时，会引发海啸，可能会摧毁沿海城市。此外，如果一个千米大小的物体撞击地球，由于大量尘埃和水汽被输送到大气中，导致地球气候发生变化，将会引发一场全球灾难。本文概述了近地小行星和彗星（近地天体-NEO）的撞击危害以及正在收集这些天体重要数据的近地天体搜索计划。它还指出了使用偏转系统减轻撞击危害的方法。进一步讨论了近地天体偏转策略和系统的关键限制以及减轻危害和疏散的成本与效益。针对未来解决近地天体撞击危害问题的活动给出了建议。
